Services for communicating with a specific person in a virtual space constituted by an electrical communication network such as the Internet have come into wide use in recent years. An example of the services is an electronic message board. For example, Patent Literature 1 below describes an information message board for household use which, on the basis of a key word automatically extracted in accordance with how the user uses content, further collects content.
Usually, each of the members who use an electronic message board can post information, such as a message, to the electronic message board, and the other members can share the posted information by viewing the electronic message board. For example, in a case where a member wants to notify information to another member to be notified, the member can post the information on the electronic message board so that (i) the information can be communicated to the another member to be notified and (ii) other members can also check the information. This makes it possible to avoid such circumstances where a plurality of members redundantly notify the same information to the member to be notified, or where none of the other members notifies the information to the member to be notified, on the assumption that some other member will notify the information to the member to be notified.